1. Technical Field of the Invention
The present invention relates to a method and apparatus for processing a plurality of sectional images of an object to be diagnosed with the use of a three-dimensional ROI (region of interest) such as spherical ROI.
2. Description of Related Art
Recently, medical imaging modalities, such as X-ray CT scanners and MRI (magnetic resonance imaging) systems, have become popular in medical facilities in which medical diagnosis and treatment is actually performed. Such medical imaging modalities are able to easily produce a large quantity of images of each patient (i.e., object to be diagnosed) in the course of medically examining or treating the patient.
For example, the MRI system has the capability of acquiring a large number of images of a patient by using a magnetic resonance imaging technique. With this technique, nuclear spins in an object placed in a static magnetic field are magnetically excited by an RF signal of a Larmor frequency of the nuclear spins. This excitement makes it possible that an MR signal emanated from the object due to the excitation is acquired and an image is reconstructed using the MR signal.
For imaging various sections of a patient using the magnetic resonance imaging, the direction of each section can be decided freely and the same region within the patient can be imaged in various different directions. Thus, this imaging capability will easily produce, if necessary, a large number of images in the process of diagnosing each patient. For a doctor's comparative observation of images, there has been a demand that the same region to be imaged be clearly pointed out on each of a plurality of images, when the images are displayed. Conventionally, this pointing-out function has been realized in various ways, such as by presentation of one or more mutual relationships between or among sections that have been imaged or by presentation of positional information about images to be displayed.
However, the conventional pointing-out techniques are not sufficient for easily and precisely supplying positional information about the same imaged region among plural sectional images. To be specific, though the same region is depicted in various sectional images, understanding where the region on any sectional image is located on the other sectional images is rather difficult for doctors or others. The reason is that, since various sections different imaging directions may also be imaged differently from each other, whereby an offset of each section is changed subtly. Such a difficulty is not limited to MRI systems, but is also true of X-ray CT scanner systems.